PDD 16246, 74385, 75494.

Fruiting body a stalked (or rarely sessile) sporangium, gregarious, and up to 1 mm tall. Sporotheca globose or somewhat flattened below, 0.4–0.5 mm in diameter. Stalk cylindrical or tapering upward, stout, opaque, typically white but sometimes ochraceous or tawny, furrowed, calcareous, short, about equal to the diameter of the sporotheca. Hypothallus discoid, membranous, white or colourless. Peridium consisting of a single layer, rugose, encrusted with lime, usually yellow to dull orange but varying from yellowish grey to honey yellow to bright orange-honey yellow to bright orange-red or reddish brown, persistent below. Columella small, conic, white or pale yellow or rarely orange. Capillitium abundant, consisting of large, angular, white, or less commonly yellow or orange lime nodes connected by delicate hyaline filments. Spores dark in mass, pale violet-brown by transmitted light, minutely warted, 7.5–10.0 µm in diameter. Plasmodium yellow or olive-green.

Decaying leaves and other types of plant debris.

Martin & Alexopoulos (1969), Neubert et al. (1995).

Although the colour of Physarum melleum can vary from off white to bright orange or yellow, the combination of a globose sporotheca on a thick calcareous stalk is usually enough to identify this species.